The publisher of the Daily Mirror considered running an advertising campaign highlighting how its titles opposed Lady Thatcher's divisive policies in the 1980s, after the former Conservative prime minister's death.

The main target of the poster campaign, which Trinity Mirror executives were considering running in the days after Thatcher's death last Monday, was to point out to the public that Rupert Murdoch's rival tabloid the Sun was pro-Thatcher in the 80s.

A mockup of the targeted poster ad reminds the public of the differing stances taken by the rival tabloids: "To the Sun she was ... Maggie", "To Daily Mirror she was ... Thatcher".

At the base of the poster is the Daily Mirror logo and the line, "Remember who's on your side".

The Sun, edited by Kelvin MacKenzie for most of Thatcher's premiership, was one of her leading champions in the UK media. Murdoch used last Wednesday's Times to pay personal tribute, praising her union-busting stance for allowing his UK publishing empire to flourish.

In contrast the Mirror titles fought numerous battles with Thatcher in the 1980s.

The Daily Mirror, the paper most likely to have been hostile in its coverage of Thatcher's demise, played it straight with its splash the day after she died with the headline, "The woman who divided a nation".

Trinity Mirror's poster campaign, which it is thought is unlikely to see the light of day, was considered as a tactical marketing strategy to remind the public that the Daily Mirror positioned itself as the people's champion versus Thatcher in the 80s during episodes including the miners' strike, which bitterly divided the nation at the time.

The Mirror titles were owned from 1984 until the end of Thatcher's premiership by controversial tycoon Robert Maxwell. The Daily Mirror was edited by Mike Molloy for a decade until 1985 and then by the late Richard Stott until 1990.

Trinity Mirror wasn't the only newspaper publisher looking to run an eye-catching ad campaign. The Guardian, publisher of MediaGuardian, appropriated Marmite's famous "love it or hate it" brand in an ad to promote Posy Simmonds' take on Thatcher in Saturday's edition of the newspaper.

The ad featured Marmite's instantly recognizable yellow and black jar with the name on the label changed to "Margaret", a picture of Thatcher, her birth and death date and the line "contains iron". The ad, which ran with the line "One woman, a nation divided", was created by ad agency BBH.

The Guardian did not seek permission to use the Marmite brand in the ad before publication, given the last-minute tactical nature of the campaign, but a spokeswoman for parent company Unilever said there would be no repercussions as the "piece agreed with the personality of the brand".

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